1. Field of the Invention
This invention is in the field of vehicle steering and speed sensitive apparatus to detect a lack of driver alertness and emit a warning thereupon, and to signify vehicle speeds over a preset speed.
2. Description of the Prior Art
Numerous systems are available which sense vehicle steering corrections during a given time period as an indication of driver alertness. If the corrections fall below a predetermined number in the given time period, a driver warning system is emitted to bring to the driver attention a reduction in his alertness. The alarm systems frequently are sounds or buzzers which would arouse a sleepy or preoccupied driver condition. It has been shown that in normal driving patterns, the steering wheel is corrected a given number of times during any predetermined time period. It has also been shown that when the corrections fall below the predetermined number, the driver is usually inattentive due to fatigue, preoccupation with other matters, or other inability. An audible driver warning system during such conditions has been shown to be effective to arouse the drive to a state of alertness to prevent a vehicle accident. Such systems have been coupled with vehicle speed sensing devices which make them inoperative below a certain vehicle speed so that when the vehicle is parked or moving at a relatively slow speed, the audible alarm will not be sounded even though the necessary steering corrections are not made within the given time period. However, such systems ordinarily require physical contact between two steering members to sense the steering corrections, or require connections outside of the operator compartment such as in the engine compartment to sense vehicle speed. Also, such systems ordinarily require extensive installation and resultant costs and due to their construction can become misaligned, require frequent repair due to the manner of their sensing functions, and the attachment to the existing vehicle hardware, with resultant added equipment costs, installation costs, and maintenance costs. Further, such systems do not provide an inverse relation between vehicle speed and the time period between steering corrections to cause the alarm to be operative. For these and other reasons, these systems have not found general usage in motor vehicles.